Showing papers on "Transmittance published in 1982"

High quality transparent heat reflectors of reactively evaporated indium tin oxide

Abstract: Transparent and heat reflecting indium tin oxide films were prepared by electron beam evaporation of In2O3+9 mol.% SnO2 onto glass in an oxygen atmosphere of ∼5×10−4 Torr. Visible light absorption less than 2%, thermal infrared reflectance exceeding 90%, and a dc resistivity of ∼3×10−4 Ω cm were obtained for 0.3‐μm‐thick films deposited on a substrate at 300 °C. Similar properties could be achieved with substrate temperatures as low as 150 °C. By antireflection coating the films with an MgF2 layer, the visible transmittance exceeded the transmittance of the uncoated glass while the infrared reflectance was practically unchanged.

Measurement of optical properties of materials in the vacuum ultraviolet spectral region.

Abstract: Measurement of optical properties in the VUV depends on photometric data rather than a mixture of photometric and relative phase data. Generally the measurement technique is that of measuring the reflected intensity at a number of angles of incidence and fitting these data to a calculated reflectance curve. The actual measured reflectance values need not always be known but are helpful in the final analysis of the data. Other more specialized methods include a critical angle method and the determination of extinction coefficients from transmittance measurements. The accuracy of the reflectance methods depends on the optical properties of the material being measured and the angles of incidence at which reflectance measurements are made. Instrumental errors and the condition of the surface being measured can also cause appreciable errors in the results. Accurate values of the optical constants can be used to characterize the electronic structure of a material and to design special reflecting and transmitting coatings for use in EUV astronomy and laboratory applications and possibly for use with excimer lasers in the VUV.

Light scattering by aggregates of large colloidal particles

Abstract: Information theory and the Rayleigh-Gans-Debye and anomalous diffraction approximations are used to obtain criteria for choosing an aggregate model. They suggest a simple one with appropriate gross features. The hollow sphere of equal mass and total volume is chosen, actually a slightly heterogeneous population of hollow spheres. The average sphere volume is that of the aggregate; the volume and refractive index of the coat are those of the particles; the volume and refractive index of the sphere core are those of the spaces between the particles. The effects of aggregation on transmitted and scattered light were measured with two transmittance photometers and a 90° scattering photometer. Observed effects of aggregation are qualitatively accounted for with this method of predicting aggregate scattering. The method is also used to survey predicted effects of aggregation of blood platelets on suspension transmittance.

Antireflection layers for GaAs solar cells

Abstract: The results of reflectance and transmittance calculation for various single and double layer optical coatings on GaAs solar cells are presented. An optimization technique has been used to calculate the optimum thicknesses of the layers which result in maximum transmission of photons at the GaAs surface taking into consideration the solar spectrum in outer space (air mass zero illumination). The effect of angle of incidence of light is also discussed. The technique used is quite general and could be used for any system of multilayer thin films of absorbing or nonabsorbing type with light incident at any angle.

Paraxial imaging and transforming in a medium with gradient-index: transmittance function

Abstract: In this paper we study the paraxial imaging and transforming in a medium with gradient index obtaining the image and transform conditions. The medium is characterized by a transmittance function at the output plane similar to a thin lens. This medium can be an element of imaging and optical data processing systems.

Method of and apparatus for restoring the light transmittance of an image transmitting optical fiber bundle used in a fiberoptic endoscope

Abstract: Exposure of a fiberoptic endoscope X-ray or y-ray irradiation causes discoloration of fiber bundle with a reduction in light transmittance and makes observation or examination difficult. According to the invention the irradiation-induced reduction in light transmittance of the image transmitting fiber bundle 52 is eliminated by visible light radiation thereto through its end using a light source 64 attachable to the exit end of the endoscope. Visible light radiation having short wavelength causes the transmittance to recover to that before irradiation in a short period of time.

Photoelectric conversion semiconductor device

Abstract: PURPOSE:To prevent the reliability of a semiconductor device from decreasing due to the reaction of metal with semiconductor device by forming a back surface electrode in a 2-layer structure of a light transmittance conductive film and a reflecting metal layer, thereby improving the conversion efficiency. CONSTITUTION:The first light transmittance conductive film CTF2 is formed on a glass substrate 1. Then, a photovoltaic power generating non-single crystal semiconductor 3 which has a PIN or P-N junction is formed on the CTF2. Then, the second light transmittance conductive film 5 having a thickness of 700- 2,000Angstrom and the second electrode formed of a reflecting metal layer 6 on the film 5 are formed on an N type semiconductor of the semiconductor 3. When thus constructed, short wavelength of 500nm or shorter is sufficiently absorbed by the light passing in forth, and long wavelength of 600nm or longer can generate photocarrier at the active semiconductor layer by the light of return after reflecting. The film 5 operates to prevent the reaction of aluminum forming the layer 6 with Si, thereby preventing the lowering in its reliability.

A Theoretical Model of Radiative Transfer in Young Sea Ice

Abstract: A four stream discrete-ordinates photometric model including both anisotropic scattering and refraction at the boundaries is presented which treats the case of a floating ice slab. The effects of refraction and reflection on the redistribution of the incident radiation field as it enters the ice are examined in detail. Using one- and two-layer models, theoretical albedos and transmittances are compared to values measured in the laboratory for thin salt ice. With an experimentally determined three-parameter Henyey–Greenstein phase function, comparisons at 650 nm yield single-scattering albedos ranging from 0.95 to 0.9997. The models are then used to compare the effects of diffuse and direct-beam incident radiation, to investigate the dependence of spectral albedo and transmittance on ice thickness, and to determine the influence of very cold and melted surface layers.

Simple method for the complete optical analysis of very thick and weakly absorbing films

Abstract: In this paper a method for the determination of the thickness and spectral dependences of the optical constants characterizing very thick and weakly absorbing thin films located on nonabsorbing substrate is presented. Within the framework of this method the positions and values of the extrema in the spectral dependences of the reflectance and transmittance are utilized for evaluation the values of the optical parameters mentioned above. The main advantage of the method is that the values of the optical parameters can be determined by means of explicite formulae with relatively high accuracy. The method is utilized for the complete optical analysis of magnetic garnet films.

Optical Properties Of Transparent Heat Mirrors Based On Thin Films Of TiN, ZrN, And HfN

Abstract: Calculations of the transmittance and reflectance between 0.35 pm and 10 pm of semitransparent films of TiN, ZrN and HfN have been performed. The calculations are based on recently reported optical constants. They show that these compounds can be used as transparent heat-mirrors. These materials show considerable higher emittance than the noble-metals but comparable or higher visible transmittance. It is also shown that the transmittance can be increased by the technique of induced transmission.© (1982) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The solar transmittance of some convection suppression devices for solar energy applications: an experimental study

Abstract: The solar transmittance of seven convection suppression devices (CDSs) has been measured as a function of both angle of incidence and azimuth angle using a large integrating sphere test facility. The CSD designs tested include a honeycomb and various slat geometries made from FEP Teflon film, and a tubular glass honeycomb. All FEP Teflon CSDs tested had solar transmittances not less than 0.94 for angles of incidence up to 45 deg, whereas for the glass tubular CSD, the solar transmittance was not less than 0.87 over the same range. The results for FEP Teflon CSDs compare well with previous theoretical and experimental studies of similar CSDs. Empirical solar transmittance correlation equations have been derived, based on a simple CSD solar transmittance model, and they match the measured performance of the CSDs to within 2 percent. The transmittance, reflectance, and absorptance of each CSD to isotropic diffuse radiation have been determined. The radiation properties data presented provides extensive information on some alternative CSD designs, some of which have not been analysed previously.

Integrating sphere for solar transmittance measurement of planar and nonplanar samples

Abstract: A new apparatus that incorporates an integrating sphere is described, which enables the solar transmittance of test samples to be measured as a function of both angle of incidence and azimuth angle. This apparatus was developed to perform measurements on both planar and nonplanar samples of larger dimensions than can be accommodated in a spectrophotometer. Solar transmittance measurements from this apparatus are compared with those from a Gier & Dunkle spectrophotometer for a range of sample materials, and excellent agreement has been found. Errors in solar transmittance measurement may arise from changes in the integrating sphere entrance port reflectance due to placement and then the removal of the test sample from the port. A correction procedure is derived to take account of these errors and is applicable to all single-beam integrating spheres.

Infrared Transmitting Germanate Glasses

Abstract: The infrared cut -off of glasses is primarily determined by the frequency of vibration ofthe cation -anion bonds In order to extend infrared transmittance to longer wavelengthscations and anions of larger sizes and lower field strengths should be used; however, physi-cal and chemical properties become poorer For silicate glasses, this cut -off is about 5 pm If germanium is used as the glass network former instead of silicon, the cut -oftmoves out to about 6 pm Of all types of glasses, the germanates provide the optimum com-bination of transmission, physical, and chemical properties While the size of glass form-ing areas for germanates is smaller than that for silicates, properties can be varied some-what to fit a particular application Expansion coefficients (25 °- 300 °C) can vary fromabout 50 x 10- / /°C to over 100 x 10 -/ /"C with mechanical hardness, Young's modulus, andchemical durability generally decreasing with increasing expansion While the cut -off isdue to the germanium- oxygen bond vibration, the shape of the transmission curve approachingzero transmission from about 45 pm to 6 pm can be significantly affected by the quantityand type and modifying oxides An optimum glass with respect to infrared transmission, lowthermal expansion, meltability, formability, and cost was selected and designated Code 9/54Originally, this glass was melted in crucibles and pressed into domes of rather poor qualityHowever, more recently a process has been devised to melt Code 9754 glass in an optical tankand then press into various shapes with standard first grade optical quality (ie, glasscontains no visible striae), a total bubble cross section of 501O mm2 per 100 cm3, and nocracks or checks The glass has a thermal expansion (25 °C- 300 °C) of 636 x 10-7 /"C, aYoung's modulus of 858 x 103 kg/mm2, and a refractive index (ND) of 1660 The minimumuncoated transmission of a 135 mm thick sample is 73% at 5 pm and 35;o from 42 pm downthrough the visibleComparison of germanates with other IR- transmitting oxide glassesThe infrared cut -off of glasses is determined by the frequency of vibration of cation -anion bonds This frequency is dependent on the mass and structural arrangement of constit-uent atoms and the interatomic forces within the structure Larger cations and anions withlower field strengths will move the infrared transmittance to longer wavelengths, however,physical properties and chemical durability become poorer As can be seen in Figure 1, theinfrared cut -off tor silicate glasses is about 5 micrometers As cations of lower fieldstrength are used as glass network formers, the cut -oft moves out to 6 micrometers forgermanates and calcium aluminates, 65micrometers for tellurites, and 875 microm-eters for the lead bismuthates Table 1

Polarization‐ and Temperature‐Dependent Two‐Phonon Absorption Spectra in InSe

Abstract: Polarization- and temperature-dependent transmittance and reflectance spectra of InSe are measured in the wavenumber range from 200 to 500 cm−1. The absorption peaks observed are interpreted in terms of two-phonon combination modes due to Γ point phonons considering the β-, ϵ- and γ-polytypes. It is concluded that the InSe crystals are of the γ-polytype. Mode Gruneisen parameters are estimated for the intralayer modes. Polarisations- and temperaturabhangige Transmissions- und Reflexionsspektren von InSe werden im Wellenzahlbereich von 200 bis 500 cm−1 gemessen. Die beobachteten Absorptionslinien werden als Zwei-Phononen-Kombinationsmoden unter Einbeziehung von Phononen des Punktes Γ interpretiert, wobei die Polytypen β, ϵ, und γ betrachtet werden. Es wird geschlossen, das die InSe-Kristalle vom γ-Polytyp sind. Es werden Gruneisen-Parameter fur die Intralayer-Moden abgeschatzt.

CaLa 2 S 4 : ceramic window material for the 8 to 14 μm region

Abstract: CaLa2S4 is a member of the family of ternary sulfides. It has the cubic Th3P4 structure, space group I-43d, with both cations on equivalent 8-coordinated sites. Powders prepared by firing oxides and carbonates in flowing H2S can be processed by a combination of hot-pressing and hot-isostatic pressing into sulfide ceramics with good infrared transmission. The vibrational absorption edge is at 17 μm. The materials are resistant to attack by water. The microhardness of the nearly 100% dense ceramics is 600 kg/mm2. Optical transmission of 55% (including reflection losses) at 14 μm has been achieved, but optical quality is extremely sensitive to processing conditions. Absorption and scattering are produced by residual pores, by second phase impurities on grain boundaries, by oxidation products such as sulfate and thiosulfate, and electronic defects arising from non-stoichiometry.© (1982) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Sub-Oxide Thin Films For An Optical Recording Disk

Abstract: Thin films of SbOx, GeOx, TeOx, MoOx, InOx and PbOx ( x is smaller than the stoichiometric value for each component ) were found to have a feasibility to be applied to an optical recording disc. Upon heating, these thin films are critically changed in their optical constants at 150°, 280°, 120°, 150°, 120° and 100°C, respectively. The contrast ratios before to after heat treatment of the GeOx, TeOx and MoOx films of 1000 - 2000 A thick are very high, they are 50, 20 and 15, respectively. Among them, the TeOx (x ≈1.1) film was excellent in both the sensitivity and the contrast ratio, and an optical recording disc was prepared by depositing the TeOx on a PMMA disc, substrate. Video-signals can be recorded and played back using a laser diode (λ =8300 A, N.A.= 0.5) at the laser power of 6 - 8 mW incident. The carrier to noise ratio at 5 MHz was in excess of 55 dB.© (1982) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

The optical properties of container glass

Abstract: Those optical properties of glass of most interest in the soda-lime-silica container composition field are refractive index, reflection, transmittance and absorption. These properties relate to measurement of internal stress, light protection, heat transmission and visual color. Spectrophotometric measurement of transmission/absorbance properties and use of the C.I.E. system to express color parameters are useful in color control to meet customer specifications.

Method for detecting the presence of a gas in an atmosphere

Abstract: Near real time remote sensing of atmospheric gases is performed using differential absorption lidar or transmission techniques. The wedge absorption remote sensor (WARS) utilizes an emission spike train of short time duration as is found in the long pulse output mode of a solid-state laser to define the on and off line absorption of an atmospheric gas and hence its concentration. The laser beam is split into a reference beam and a transmission beam which passes through the atmosphere being tested. The two beams are detected and amplified, and them digitized. Comparing the ratio of the digitized reference signal to transmitted signal for each spike in the spike train yields a set of transmittance values as a function of wavelength. When the digitized reference and transmitted signals are plotted, a wedge of data points results. The ratio of the upper and lower slopes of the wedge yields the absorption coefficient and concentration of the absorbing gas.

Stray light measurement and compensation

Abstract: Methods for stray light measurement and compensation in spectrophotometers are disclosed In one exemplary embodiment, stray light is determined as a convolution of a selected detected radiant power spectrum and a monochromator slit function Such a stray light measurement may be made with or without the sample in an optical path between a source and detector within the spectrophotometer When made with the sample in the optical path, the resulting stray light measurement may be used to compensate sample absorbance or transmittance measurements In accordance with another embodiment of the present invention, sample absorbance or transmittance may be compensated in a method including measuring sample detected radiant power at a wavelength outside an interval of significant detected radiant power within which a sample measurement compensated for stray is desired

Evaporative Thin Metal Films As Polarizers

Abstract: Thin metal films have been fabricated by vacuum evaporation, which polarize transmitted light at near-infrared and visible wavelengths. Polarization of normal-incidence light was observed for silver, gold and copper films made by this technique. The polarizing films were produced by directing a beam of metal atoms onto the smooth surface of an optically transparent substrate at a large angle of incidence. The film structure revealed by electron-microscope examination is a dense array of parallel metal whiskers aligned opposite the direction of the incident metal atom beam. Polarization is produced by the hertzian parallel-wire effect, which is also the polarization principle of the conventional wire-grid polarizer. The resulting polarizer material can be produced in sheet form or applied as a coating to optical elements.© (1982) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Atmospheric aerosols investigated by inversion of experimental transmittance data.

Abstract: The Twomey-Chahine inversion algorithm is applied to experimental atmospheric transmittance data in the 0.4–2.4-μm wavelength range and atmospheric aerosol size distributions deduced. The conditions for successful inversion of transmittance data are investigated in numerical experiments, and it is shown that too small a wavelength range results in a Junge-type distribution in all cases and that noise in the measurements in excess of 4–5% results in inversion artifacts.

Magneto-optical head

Abstract: PURPOSE:To improve reliability of an optically reproduced signal, by dividing a reflected light beam sent from a storing medium into two parts by a beam splitter and distributing successively a 1/2 wavelength plate, a polarized beam splitter and a photodetector on the optical axis of each split beam. CONSTITUTION:For a storing disk 1 obtained by sputtering an amorphous magnetic thin film of CdTbFe, etc., a magnetic thin film is formed on a recessing/ projecting guide track in order to obtain the trace error information. The light given from a laser device 2 is transmitted via a polarizer 3, a half prism 4 which increases the magneto-optical revolving angle produced in response to the state of magnetization of a storing medium, an objective lens 5 which forms a micro-spot on the magnetic thin film, a spot lens 6, a beam splitter 7, etc. Then about 1:1 correspondence is secured between the transmittance and reflection factor of S and P waves. In addition, 1/2 wavelength plates 8 and 9 are provided to change the replacement of revolving angle of the reflection information light in the prescribed direction.

Non-contact sensing apparatus and method for polymer melt temperature profile determination

Abstract: Remote measurement of temperature variations within polymer process melts is performed by irradiating the melt with a collimated radiation source such as laser light and relating the transmitted radiation to the temperature distribution within the melt. A method and apparatus for temperature profile determination is based upon the variation of light transmittance through the melt as a function of temperature and wavelength of the incident light.

The Measurement of Longwave Radiation Properties upon Plastic Films Used in Greenhouses

Abstract: Due to the rising cost of heating oils in recent years, the subject of heat conservation on a greenhouse has become more important. In this aspect, the plastic films used for reducing heat losses must have low transmittance property for longwave radiation, also need to have low emissivity. The properties of plastic films which affect on the transfer of energy are important.The paper discusses the measurements of reflectance, transmittance, and emissivity of longwave radiation (thermal radiation) upon various plastic films used for crop protection in agriculture, particularly in a greenhouse.New measuring methods for reflectance and emissivity were presented, and the previous transmittance calculations (Hagiwara and Horiguchi, 1972) were improved by using newly obtained reflectance values. The transmittance values obtained from the present study are about 2-5 percent larger than the values obtained from the previous study. The reason for the discrepancy may be due to the negligence of the reflectance term in the previous calculation.